Definition of "Lalage"

"What's her name?""Lalage." She pronounced it as a dactyl, the g hard. Still she could not raise her eyes. " Mr Rossetti approached me one day in the street. […] He himself proposed the name. He is her godfather." She murmured, "I know it is strange."

1969, John Fowles, The French Lieutenant's Woman, Penguin, published 1981, page 359