Indeed, the orchestral arrangement is very effective. It also seems to have been written in a minor key. In 1967, I was neither a Beatles fan nor an acid head--I listened mostly to Oldies on KWIZ, but when I occasionally surfed over to LA's premier Top 40 blaster Boss Radio 93 KHJ, I enjoyed hearing the DJ's play "Walrus."
Not only is it not in a minor key, but there isn’t even a minor chord in it.