"Come to think of it, where's Tanimoto?" "Same as ever — acting like a lone wolf."
Literal
Speaking-of, Tanimoto-[-kun] [topic-は]? / As-usual one-animal wolf put-on-airs-[is-ている] [よ].
そういえば ('speaking of / come to think of it') is a discourse opener introducing a newly recalled topic. 君 (kun) is a familiar address suffix for male peers and subordinates. 一匹オオカミ literally 'one-animal (counter for small animals) wolf,' the Japanese counterpart to English 'lone wolf.' 気取る here is the lighter 'act/pose as,' as in 探偵気取り ('fancying himself a detective'). ~気取っている = 'going around pretending to be / acting like.'