I'd say the fact that he's in The Lodge would explain it pretty much -

however I do wonder what the connection is exactly between this and whatever it was that happened before - the German girl comes in and says she has car trouble or something, Bobby & Shelly say too busy jumpstarting the old man...[b]again[/b] - which I'd think would indicate some sort of re-occurance, but I don't remember anything special happenning 'before' [I can't remember where it's from, the pilot, I think?]

That scene with Heidi is almost exactly like one from the Pilot... Same dialogue, same Heidi's laugh,... A nice artistic touch from Lynch to say that the circle is completed, closed. One of the last scenes with Josie also is a replica of the first one seen in the Pilot, with her looking at the mirror...

Though Earle is a good candidate, there's also evidence that the LMFAP is the one speaking through Sarah... He is the one who we inmediately see in "the Black Lodge with Agent Cooper" and the voice we hear saying "I'm waiting for you" sounds like his... Besides, if the Giant instead of using a human vessel to communicate with Coop used some kind of 'medium' (Droolcup), it's very possible that the LMFAP was using someone like Sarah... But as I said Earle is a good candidate too, the quick shot of his face over Laura's dopp looks like an indication that after all, before being 'owned' by BOB he managed to control some of the BL power... He seems to be in control of Annie too...