How will Lord Voldemort die ?

Following on from the frankly unsurprising news that J K Rowling has announced that at least two major characters will die in the final Harry Potter book, I have been discussing with other HP readers, whether or not Harry can actually kill Lord Voldemort - which then led into a conversation about the death of Quirrell. One of those with whom I was discussing the issue, believes that Harry is the one who killed Quirrell, even if he's not morally responsible (like a patient who's weak dying of a cure, which means the doctor is not morally responsible for the patient's death). I don't agree with this view and looked to see just what J K Rowling wrote in Harry Potter and the Philosopher's Stone:

Quirrell rolled off him, his face blistering too, and then Harry knew: Quirrell couldn't touch his bare skin, not without suffering terrible pain - his only chance was to keep hold of Quirrell, keep him in enough pain to stop him doing the curse.
Harry jumped to his feet, caught Quirrell by the arm and hung on as tight as he could. Quirrell screamed and tried to throw Harry off - the pain in Harry's head was building - he couldn't see - he could only hear Quirrell's terrible shrieks and Voldemort's yells of 'KILL HIM ! KILL HIM !' and other voices, maybe in Harry's own head, crying, 'Harry! Harry!'
He felt Quirrell's arm wrenched from his grasp, knew all was lost, and fell into blackness, down ... down ... down ... (Chapter 17)

I read this as Quirrell still being alive when Harry blacks out - which is at the same time that Dumbledore pulls Harry and Quirrell apart: Harry can still hear Quirrell's shrieks in the moments before he passes out (I'm fairly sure that at least one of the voices he hears saying his name is Dumbledore), which suggests to me that Quirrell didn't die until after Harry blacked out. Of course, he may have died from the effects of Harry hanging on to Quirrell's arm, but I have always interpreted Dumbledore's comment that Voldemort left Quirrell to die as Dumbledore glossing over the fact that Voldemort actually killed Quirrell when he detached his essence from Quirrell's; I've always assumed, knowing that Voldemort was scared of Dumbledore and that Voldemort at that point is very weak, that Voldemort abruptly fled from Dumbledore and in doing so, Quirrell died of shock. Does anyone interpret events differently ?