well, the arms were replaced today. Expensive, but I did get 10% off. The tech showed me the old arms, well, a piece of it, since they had to cut off the portion that went to the camber cam.
I mentioned to the tech that the May alignment went OK, so why would things seize up over the course of a summer? He said that it was probably because, while lowered, the car was near the target spec and the cam did have a bit of adjustment (which was rotating the bushing). So my stuff must've frozen up over the winters (I bet my front camber was barely touched in all the alignments I've done before lowering, it's mostly the toe that got out of whack). If I went to this dealer in May, they probably would've spotted the problem right then (and it would've been warrantied). And that also means that I didn't break anything in the garage when I tried turning it (it was already broken at least since May).
The car runs great now too.
I also had my engine compression checked and it passed with flying colors (at or above spec) at 55K miles.