Only Cocteau Twins could make “Frosty the Snowman” ecstatic and iridescent. Such rarities flesh out an evolution from sepulchral gloom to starlit bliss, as do singer Elizabeth Fraser's guest appearances, like her spellbinding turn amid sax and piano on Dif Juz's "Love Insane." Sweeter than the better-known "Song to the Siren," This Mortal Coil's "Another Day" weaves her a billowing bed of strings.