My own opinions:
Wind: Lyapunov, Transcendental Etude No.9 in D major, 'Aeolian Harps' (I prefer this musical picture of said instruments to Chopin Op.25 No.1, but that's just me).
Water: I suppose 'Reflets dans l'eau' is the logical choice here, or perhaps 'Poissons d'or' from Book II of the Images? Or the 'Ocean' etude by Chopin if you'd rather show violent waters.
Earth: 'Paysage' seems a good choice, or 'Wilde jagd'.
Fire: Mephisto Waltz No.1, perhaps? I've always thought 'En rhythme molossique', the D minor etude from Alkan's minor key etudes, evokes images of a fire that slowly dies out during the coda of the piece despite efforts to burst into life again. But that's probably just me.
I can say that you should balance energetic pieces with more laid back ones; so, from the above list, pairing 'Wilde jagd' with one of the Debussy pieces or 'Paysage' with the 'Ocean' etude would probably work. Or else take 'Paysage', one of the Debussy, and play the 'Winter Wind' etude.
Of course, the above selections are rather skewed toward the early Romantics, so it's far from the ideal list.