O.R.T.F. stands for "Office de Radiodiffusion Télévision Française" = the then single entity for French radios and TVs (1964-1974)
Before 1964, it was named RTF (Radio Télévsion Française), and in 1974, O.R.T.F. became Radio France (while the TV Channels spin off and were split in different entities).
Alternative names include: Orchestre Radio-Lyrique, Orchestre Lyrique de RTF (before 1964), Orchestre Lyrique de l'ORTF (1964 to 1974).
In 1975, the Orchestre Radio Lyrique De L'ORTF was disbanded with musicians moving to Orchestre Philharmonique De Radio France and Orchestre National De France.
In a short transition period (between the name change in August 1974, and the orchestras merge completion in 1975), this orchestra was named: Orchestre Lyrique De Radio-France.