According to Partridge "A shirker: 1914-18. ('Sapper' in The Lieutenant, 1915.) Ex 'lounge lizards' disporting themselves at Maidenhead." And lounge-lizard: "A sleek adventurer frequenting lounges in the expectation of women, their money and caresses: US s. (1923), anglicized by 1925; by 1935 coll. (Krapp's prophecy as to its lack of viability has been proved false.)" Marvellous.