richard , it is in my opinion better to sing and then have a pause the coming of my dear, it creates a dramatic effect. i would suggest you listen to the recording made for the film far from the maddding crowd, the singer was isla cameron, although julie christie did the miming
http://ie.youtube.com/watch?v=ojVFPeU0YQU here is another version
http://ie.youtube.com/watch?v=PtQCmZII-DQ&feature=related