Correct pronunciation: Your guess is as good as ours
Incorrect pronunciation: Anything you might attempt
This is what happens when the Japanese try to emulate the French. If our resident Japanese speaker can't even make it through the title unscathed, what chance do the rest of us have?
Our suggestion - go with it. With so many similar sounds stringed together like that, the title is obviously meant to be silly and fun. If you're hiccupping through it now, imagine how the Japanese feel with their original title, PoPoRoKoRoisu...
We say PoPoLoCrois is supposed to be mispronounced. Do your worst.
Above: We want to name a basket of kittens after it