Many (most?) of the earliest settlers of Union County came from Rowan Co., and then many over the next few years many moved south into Alexander County.Virtually all early family names from Union can also be found in Alexander.The Alexander Co. census indexes I have show many Lences (with spelling variations).
The Union County published marriage index shows 71 marriages of Lences (with spelling variations) and 27 of Hartlines.
One of possible interest to you is Peter Lence Jr., who married Caroline Bilmarry Tata (hey, I don't make these names up!) on 26 January 1862, recorded at Book 2, page 317.