I'm not sure how that link supports your assertion I'm wrong. Can you be a little more specific?
In your example, "then" is the conjunctive adverb.
Edit: By the way, I love having grammar discussions on the internet. Let's make a grammar discussion club, so we can really go at it, and maybe try and keep the grammatic national socialism out of hackernews.
Well played -- by way of elaboration, a deft avoidance of Godwin's Law.