Forum ate my post.
Starmaker: Try temporarily uninstalling the high-res patch. (It won't mess up your saves.)
billy_k: I read that suggestion elsewhere, and it didn't work.
I've just played another character to this point, and I noticed something. I again didn't see Joachim as I came into town, but as soon as I started the conversation with Virgil after resurrecting him, I saw Joachim appear for a brief moment at the door of the room, but he disappeared before walking in.
If Virgil runs away, you're supposed to meet Joachim in the basement, not at either city entrance. It's definitely a buggy proximity trigger. Try uninstalling HR, cleaning cache (run CleanCache.bat) and going through the basement scene again.
Success story:
I use 1680*1050 resolution. About everything seems to work just fine. The only thing that does not work is when Joachim is supposed to come to the underground room at the Sobbing Onion after Virgil is ressurrected. One time I managed to see a glimpse of him near the double doors, but then he just vanished. So I had to uninstall the patch for that event to work properly.
If it fails, here's what Muro has to say:
All Joachim functionally does is provide some linear dialogue. It doesn't affect anything in the game and you will not miss anything because of him not showing up in your game.
My suggestion is familiarizing yourself with the dialogue
here (all he says after the conversation is over is a "Good luck to you, Living One." floating line) and pretend that it happened in your game.