When does Quilty start following Lolita?

Hi,

I'm confused about when Clare starts stalking Lolita himself.

I know that Quilty's uncle was Lolita's neighbor, so Lolita may have met him at a younger age.

I know that the first time Quilty appears to Humbert is at the Enchanted Hunters hotel.

But how did he know to go to that hotel? Was he already stalking them then? If so, how did Lolita tell him to go there, or even know what hotel Humbert was headed for? Was it McFate that brought him there?

It's bothering me for some reason. Thanks for any input.