Don't know this fantasia, is it a concerto piece?
In English it's called Fantasia on Russian Folksongs, although in Russian it is Fanatasia on Themes of Riabinin (or Ryabinin?). It is a piece for piano with orchestra and is quite short (about 10', IIRC).
Arensky was one of the most prodigiously gifted Russian composers, and a true master of miniature. Unfortunately, alcohol, women, and love for entertainment kept him way too busy from disciplined and consistent work, and probably resulted in his early death.
His Suite no. 1 for two pianos is terrific. If you are able to find, check out the Waltz with Garold Bauer and Ossip Gabrilovitch. It is truly astounding performance in the best traditions of salon music making, full of grace, elegance and air, and with highest taste so often missing in the piece.