How useful do you think Mr. Lloyd's idea was, that Jane should leave her aunt's house? What, if anything, will she gain from her stay at the orphanage?

Mr. Lloyd's idea was very useful in that Jane was unwanted in her relatives home and treated poorly. The orphange wasn't much better, but it did afford Jane a good education and the propect of employment.... something that would also give her a sense of freedom and self-worth. In context, this opportunity leads her to Rochester and love.