WNW: "Then" Help

Reader question day here on Word Nerd Wednesday.

UPDATE: I originally wrote this post on a headache brain. Hence, I used the term contraction when I meant conjunction. (Yeah, I know. DUH. Like those two things are anything like one another.) Thanks a million to the alert reader who pointed it out so I could fix it and not look like a total idiot into the eternities.
I was recently asked something akin to the following (rephrased since I didn't get around to asking to use it . . . but I'm just...