This is a topical word as I write this: the cardinal electors are, during the day, being locked into their pressure-cooker, the Sistine Chapel, to determine who will bear the keys of St. Peter. They are all sequestered in the Vatican, that enclave in the middle of the Eternal City, locked in debate and prayer and voting. Literally locked in: the doors of the Sistine Chapel are locked.
That is why this gathering is called a conclave: it is held in a conclave. The place it is held is a conclave because it is locked. Here is the key to this word: con ‘together’ and clavis ‘key’. There’s that clasping coarticulation of the /kl/ – so good for occluded and occluding things: clasps, clutches, cloaks, closets of clothes, clouds, cloisters, cliques and clubs (but also clergy and clemency and many other less closed words). We see the clave root in other words too: autoclave, a high-heat, high-pressure cooker or sterilizer – from French marmite autoclave, ‘self-locking pot’ (if you own a pressure cooker, you get the picture); enclave, a territory locked in (surrounded) by other territories; clavicle, the collar bone – over which papal regalia may be draped, such as the keys of St. Peter.
Those keys, yes. They’re on the flag of the Vatican and in assorted other papal places. See a picture of them at en.wikipedia.org/wiki/File:Emblem_of_the_Papacy_SE.svg. Did St. Peter carry those keys? No, they symbolize what Jesus said to Peter in Matthew 16:19: “I will give you the keys of the kingdom of heaven, and whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.” It is perhaps fitting, then, that once the new pope is elected, the doors of the conclave are unlocked, opening once again to public view the vision of heaven painted on its ceiling by Michelangelo.
But that is not quite yet. The assembled hordes of newspeople outside (keeping their distance so their cell phones work – there are mobile phone jammers under the floor of the Sistine Chapel, preventing any cardinal from live-tweeting the event) will have to key in nothing more than bootless (and red-shoe-less) guesses. They might as well be standing above the Large Hadron Collider while it’s busy smashing atoms. Nothing is known during; only the result is revealed: God particle or God partisan, as the case may be.
The result, in this case, will be known by the colour of smoke produced by a special stove. The bells of St. Peter’s will also ring. I do not think anyone will blow a conch, but it would seem suitable, if it were done in the right key.
Sesquiotica 
I was always told that full sentences following a colon should begin with a capital. And I thought it was a reasonable style rule. Not your preference obviously, but may I know why? Thank you!
It’s optional. One may choose either, depending on one’s taste and sense of flow. In this case, a capital might have given the sense that the opening statement was leading into the entire following paragraph, whereas my comment on the topicality was related solely to the description of the currency of the action and thus confined within that single sentence. A capital gives a full new start; a lower-case makes it clear that this is all part of a set.
“I was always told” is, in my experience, the standard introduction to fake and baseless “rules.” I don’t know who always told you (most likely someone with less authority than they pretended to have), but you are now being told otherwise, and you may confirm it by checking an authoritative usage guide (e.g., the Chicago Manual of Style).
Arbitrary rules that serve only to limit the expressive power of communication without adding clarity have no reason for invention and imposition. There will always be people who want to nail things down and say “no, no, no.” But “no, no, no” is not a useful principle for effective communication, only for controlling others and for obsession and compulsion.
I agree: the uppercase for a full sentence after a full colon is a limiting rule. Should have checked CMoS. That said, in one of your earlier posts, you have a beautiful comment on the colon: “A colon is like a pair of eyes, looking expectantly.” That tells you everything about the usage.
yes, yes, yes