After his studies at the Paris Conservatory (first prize in piano, chamber music, counterpoint, ondes Martenot and composition with Darius Milhaud), Eloy followed the teachings of Henri Pousseur, Hermann Scherchen, Olivier Messiaen, Pierre Boulez and Karlheinz Stockhausen at Darmstadt summer school. In 1961-63, he was a student in Pierre Boulez' composition Master Class at the Bâle Musikademie (Switzerland). Meetings with Karlheinz Stockhausen within the framework of this class.