MDBG and Baidu provide a pronunciation of 咯 (as in the sentence-final particle indicating that something is obvious) as lo5. "lo" isn't listed on Wikipedia's pinyin table, and I thought only bo/po/mo/fo could drop the u from -uo. Is this the standard pinyin? Is "lo" pronounced the same as "luo"?
According to yabla, 'Io' is a valid pinyin. Quoting yabla:
to cough up
(final particle similar to 了, indicating that sth is obvious)
Example Usage just for that middle one(from yabla):
English: Ha ha ha ha! We are back. -You are back. You are back.
A pinyin table from allsetlearning:
That proves to me that lo is a valid pinyin.