I can't help you, but I found this:
en.wikipedia.org
Excerpt:
Most of "Lucy in the Sky with Diamonds" is in simple triple metre (3 4 time), but the chorus is in 4 4 time. In the song, the structure modulates between musical keys, using the key of A major for verses, B-flat major for the pre-chorus, and G major for the chorus. It is sung by Lennon over an increasingly complicated underlying arrangement which features a tambura, played by George Harrison; lead electric guitar put through a Leslie speaker, played by Harrison; and a counter melody on Lowrey organ played by McCartney and taped with a special organ stop sounding "not unlike a celeste". Session tapes from the initial 1 March 1967 recording of this song reveal Lennon originally sang the line "Cellophane flowers of yellow and green" as a broken phrase, but McCartney suggested that he sing it more fluidly to improve the song.
~Bob