I can't pull out my reference books to double 
check myself (they're all packed and the only one 
on top doesn't say), but I am sure that parts of 
the Lion King (as well as Aladdin and Mulan also) 
were done with cels.

I think that what you might have heard is that 
The Little Mermaid was the last Disney animation 
to be done *completely* by hand. (Although, I had 
thought they did parts of the storm scene at 
least with CG. . .)  I have heard people say that 
of Little Mermaid before.

If you're really dying to know for 100% certain, 
ask me again in July when I unpack my books. ^_^

Many Sharp Smiles,
--Drac