Dear Anna,I couldn't find the words to the song, but I did find some information about the horse, Arkle. "Arkle was more than just one of the greatest steeplechasers that Ireland ever produced; he was also a symbol of the confidence which swept this country in the boom years of the 1960's, particularly when he won three Gold Cups from 1964-1966." Arkle was put down in May of 1970.
I hope someone can find the words to the song. Do you know the name of CD or the name of the group that recorded the song? That information might help the search.
-- Áine