My best guess is that legally, it's Lane-Kent. At work, she can have her byline still be Lane, and her co-workers can call her Ms. Lane if they aren't close enough to call her Lois. And in her personal life, she can use Mrs. Kent when she wants to -- and Mrs. Lane-Kent when she's signing things, lol. *shrugs* It's what I'd probably do if I was already well-established in a profession like journalism and was getting married to a wonderful man like Clark (hyphenate and use whichever part(s) applicable to the situation, that is).