They're certainly based on arpeggios, but there is always (to me) a clear note in each section of arpeggio that form the melody, in the sense that if I were to

They're certainly based on arpeggios, but there is always (to me) a clear note in each section of arpeggio that form the melody, in the sense that if I were to hum the song, I would hum that sequence of individual notes.