Early this morning, two particles of my previous understanding of music came colliding into one. For more twenty years I’ve known Steve Forbert as a stalwart player in American roots and pop music, a singer-songwriter with a small but loyal following. Although I never pursued his music, I’ve known him to be a critic’s favorite. In another corner of my mind is “Romeo’s Tune,” a lovely, saccharine tune spinning somewhere on an island of one-hit wonders. Not until today, when this song appeared during my morning run, did I know this was Forbert — hos big (and only) commercial break-through. It’s like knowing two separate people for decades, never knowing they’re siblings.