so what are you blood sugars looking like now?
It's 2pm now so you're 60% through the day with no basal. If you take any lantus now, theres likely to be overlap overnight (which is when you'd really least want to be experiencing overlap and increased hypo risk). Because it's so late in the day I probably wouldn't take as much as 50% of your dose now - you might consider more like 30% if you blood sugars are looking particularly high.
Do you take bolus insulin too? If so you could use that to correct highs instead and avoid a lantus overlap and just take your normal lantus dose at bedtime instead.