Complex sentence: Rushton suggests that unlike the other five songs, this one may make use of existing music, written for an abandoned cantata, "Erigone", and this possibly explains why in this song alone Berlioz cut and rearranged Gautier's verses.
Split into simpler sentences: Rushton suggests that unlike the other five songs, this one makes use of existing music, written for an abandoned cantata, "Erigone". Rushton comments that if this is so, it may explain why in this song alone Berlioz cut and rearranged Gautier's verses.