Cecil Behringer developed a lugged-brazed titanium frame. I don't know what filler alloy he used, but the brazing was done in a vacuum furnace, which I doubt you have access to. Sadly Cecil is no longer with us, so we can't ask him. Here's an article about the Behringer frame, which maybe has details on the filler alloy (dunno, I haven't read it in years).

Titanium will burn in air at some elevated temperature, so I doubt brazing it with a torch is going to work. But if the braze-ons aren't too expensive, maybe buy two pairs and try it on a scrap of steel before committing to braze it on a frame you like.