Does LV know Snape is at Hogwarts?

[JoAnna]

No: HPFGUIDX 95981

Amanar wrote:

<<<Well, here's where snooping pays off :) Let's get back to that
scene. Harry, fed and sleepy, looks up at the staff table (alas! no
books within reach to provide quotes). And as *Quirrel turns his
head,* Snape looks straight at Harry and his scar burns. If Quirrel
looked away, it means that the evil Lord inside his turban was
looking straight at Harry, and we've already seen LV causing Harry's
scar to hurt him. And remember how, at one of the last chapters
(before the trio gets past the trapdoor), Harry complains that his
scar *had been hurting before,* but not as strongly as just then?
Harry was very near LV all year. Obviously, that had affected his
scar, but he didn't connect it with Quirrel's presence. Who would?>>>


and Strongbad (love that name! Huge homestarrunner.com fan here!) 
wrote:

<<< Voldy (in Quirrel) was at Hogwarts with Snape (not too quick are 
you DD?). He heard Snape threaten Quirrel about the stone. LV knows
Snape is a traitor, right?>>>

Now, I don't have my copy of PS/SS handy, so please correct me if 
I'm wrong -

WAS Voldemort possessing Quirrell during the entire Hogwarts year?  
I was under the impression that Voldemort did not actually *possess* 
Quirrell until midway through the year.  Can anyone with a copy of 
the book confirm this?

As for "Voldie knows Snape's a traitor," I disagree.  I believe that 
Snape was and is a double agent - LV believes Snape is spying on DD 
for LV whereas Snape is really spying on LV for DD.  So when Snape 
threatens Quirrell in PS/SS, it's possible he told Quirrell he was 
doing so on DD's orders (after all, Harry only heard *part* of the 
conversation between Snape and Quirrell in the FF), thus LV believes 
Snape is still keeping up the "ruse" with DD in hopes that when LV 
returns, Snape can continue being a spy for LV.  (I hope that makes 
sense!)

- JoAnna