I've only ever seen it as 'pon, which like wav'ring or 'neath, doesn't indicate to me a new word, just a poetical elision of an unwanted syllable. At any rate,

I've only ever seen it as 'pon, which like wav'ring or 'neath, doesn't indicate to me a new word, just a poetical elision of an unwanted syllable. At any rate, word or not-word, it's rare enough that I'd think it an error if I encountered it in a typing improvement program from 2015.