Thank you for your reply. It's a good thought, and makes sense, but that's not the issue.
The lacie drive is definitely engaged when itunes opens. If it weren't, then itunes wouldn't be able to find any of my music, rather than just random albums here and there.
I always make sure the external hard drive is engaged before opening itunes, because I don't want any automatic downloads (podcasts) to load to the wrong place.
Thanks again, but I'm still hunting or an answer.