This is a splendid example of a mondegreen: a ‘mishearing or misinterpretation of a phrase, typically a standardized phrase such as a line in a poem or a lyric in a song, due to near-homophony, in a way that yields a new meaning to the phrase’.
For those of you youngsters out there, this is from the song All By Myself.
It is misheard as Obama’s elf through (i) vocalization/deletion of /l/ in all; (ii) smoothing of the diphthongs in by and my; and (iii) perceived linking between (Obama’)s and elf.
If the s in Obama’s had been voiced (e.g. realized as /z/), however, it would have been perfect.