If you were going to go with something from the Allure line, AHEB is a better bet. It's got a lovely smooth lemon that lasts a surprisingly long time.
Outside of that, you can skip a lot of commonly mentioned citrus frags - Ferre Cologne, Bergamote 22 and even Eau Sauvage (despite my fondness for the latter 2) - as they're a bit ascerbic, at least in the openings.
Jo Malone does some cracking (though exorbitantly priced and short-lived) citrus colognes, but they'd suit the office perfectly.
Acqua di Parma's Colonia is quite smooth as well, as is my usual recommendation West Indian Limes by Crabtree and Evelyn.
There's always Hermes' d'Orange Vert, too, which I'm sure will be mentioned a lot.