Elcourt was the show's musical director, and wrote the songs. On screen, he was featured as part of the resident Rue Sésame singing group, "The Trio Sésame", with Denis Demoulin and Claude Sonneville (who performed the singing voices for the Muppets, Mordicus and Toccata). The three were French folk singers, and had not worked with each other before the show began.
Elcourt is featured on the albums:
- Les Chansons de 1, Rue Sésame (1978)
- Vive... La Rue Sésame (1978)
- Le Reveil de Mordicus (1978)
- Le Trio Sésame Chantent (1979)
- On Chante dans la Rue Sésame (1980)
- 2 Nouvelles Chansons de 1, Rue Sésame (1981)