Emma Calvé was a good friend to d'Hardelot and did much to bring her songs to notice.
Most of her life, d'Hardelot was engaged in teaching singing and diction at her home in London and many of her pupils attained success.
Her first real success as a composer was won with "Because", though her song "Sans Toi" had previously been favorably received.
She was singularly successful as a writer of songs, in which she combined French delicacy with English solidity.
Few women composers became more popular in the early 20th century than did d'Hardelot, and her success was won on merit alone.