lulu
slang (orig. U.S.).

[Of obscure origin.]
A remarkable or wonderful person or thing; freq. used ironically; also attrib.
1886 Lantern (New Orleans) 10 Nov. 6/3 Farrell's two baser was a lu-lu.

the early hyphenated form suggests that maybe this wasn't based on the name. there was an old card game called loo (from lanterloo) in which the ante was called the loo (variant lu) which could be limited or unlimited. there might be some connection (this is a total guess on my part!)
the "two baser" sounds like baseball phraseology - a two-base hit.