"Esq. is ... not used on oneself, e.g. neither on a card (which bears Mr. [sic]) nor on a stamped-and-addressed envelope enclosed for a reply * * *" Alan S.C. Ross, "U and Non-U: An Essay in Sociological Linguistics," in Noblesse Oblige (Nancy Mitford ed., 1956). But somehow, the idea has gotten out that Esq. is something you put after your own name ....—Garner, A Dictionary of Modern Legal Usage (2d ed.). Don't do this, folks. Not every reader will infer that you are ignorant, naive, or self-important, but in a profession where image counts, it's a silly mistake to make.
... Nancy Mitford? Yes, Nancy Mitford.