masc. proper name, from O.Fr. Lorenz (Fr. Laurent), from L. Laurentius, lit. "of Laurentum," a maritime town in Latium, lit. "town of bay trees," from laurus (see laurel). The It. form is Lorenzo. A popular given name in the Middle Ages, as a surname it is attested from 1141.
Larkin is a pet-form. For some reason, the name since at least 18c. has been the personification of indolence (cf. also Ger. der faule Lenz "Lazy Lawrence"). But in Scotland, the pet form Lowrie has been used for "a fox" (c.1500), also for "a crafty person" (1560s).