[2] Orphelin spent most of his career at the Environment and Energy Management Agency (ADEME),[3] where he was chief of the economy, evaluation and observation department and then director of research and development.

He also acted as adviser to Michèle Pappalardo, then as chief of staff to Chantal Jouanno and Philippe Van de Maele.

From 2007 to 2010, Orphelin was part of the representatives of the State College in the groups of Grenelle de l'environnement and works in particular on the building plan and on the tax measures whose contribution energy climate.

[12] In July 2019, Orphelin voted against the French ratification of the European Union’s Comprehensive Economic and Trade Agreement (CETA) with Canada.

[13] Amid the COVID-19 pandemic in France, Orphelin backed a public petition calling on consumers to “not buy any gifts” from Amazon for the holidays in 2020.