This may have been addressed already, but why doesn't Harry suspect at this point that Quirrell is Voldemort, or at least working for Voldemort?

This is especially puzzling after we get to hear Harry's thoughts on what happened to Hermione in 85.

Now, maybe I'm suffering from obvious-in-retrospect syndrome here, given that I did not realize Quirrell was Voldemort until V ernq Ryvrmre'f fvapr-ergenpgrq fgngrzrag gung Dhveeryy vf Ibyqrzbeg. But that was before the Stanford Prison Experiment arc. Relevant facts in that and the Taboo Tradeoffs arc:

• Quirrell broke Bellatrix out of Azkaban
• Voldemort is the only person in the world with an obvious motive for wanting to break Bellatrix out of Azkaban, and is who everyone else thinks is responsible
• Quirrell uses at least one alternate identity, and Harry suspects him of having many more
• Quirrell's explanation of his motives for breaking Bellatrix out of Azkaban (she might know something useful, also a whim, see Ch. 60) aren't terribly satisfying
• During Hermione's trial (Ch. 80), Harry thought that it "seemed horribly and uniquely plausible that the entity who'd Memory-Charmed Hermione was the very same mind that had - made use of - Bellatrix Black."
• In Ch. 85, we see Harry is taking the possibility that Quirrell was behind the plot against Hermione seriously.

What pieces of evidence doesn't Harry have here? He doesn't know about horcruxes so he can't make the connection to Quirrell's story about the Pioneer Plaque, and Hermione hasn't (yet?) told Harry what she's realized about what Quirrell did and why (Ch. 84). But Harry still has a lot of evidence.

The one thing that may be tripping Harry up--and was tripping me up until the moment I mentioned in rot13 above--is that Quirrell seems very serious about his "I don't want to be a Dark Lord, I want you to be a Dark Lord, Harry!" line, and it's hard to make sense of Voldemort taking that attitude.

Maybe Ridvolquir interpreted the prophecy as saying he can't defeat Harry until Harry becomes a Dark Lord???