(From the RDB Files)
In vol. 5, p. 257 the respected The Expositor's Greek Testament says: "In the present case [Jude 1:4], however, the second noun (kupiov [“lord”]) belongs to the class of words which may stand without the article .... A similar doubtful case is found in Tit. ii. 13.... Other examples of the same kind are Eph. v. 5 ... 2 Thess. i: 12 ... 1 Tim. v. 21 (cf. 2 Tim. iv. 1) ... 2 Peter i. 1."
Even trinitarian scholar Murray J. Harris notes, in discussing Eph. 5:5, that “It is highly improbable that Paul would introduce a profound, unqualified doctrinal affirmation (Christ is theos) in an incidental manner [such as here], in a context where the assertion is not crucial to the flow of argument.” - p. 262, Jesus as God, Baker Book House, 1992.