I've been a type 1 for 37 years and believe it or not, also forgot to take my lantus last night. I very recently (three days ago) started splitting my dose due to doctor's recommendation so it's only half a dose I missed.
Here's what I would (and will) do, but you should check with your doc to get his/her recommendation - Watch your sugars today - test often - about every two hours - and use your short acting insulin (at your normal carb/sugar ratio) to bring it down when it gets high. Then take your lantus tonight as normal.
Good luck!
I've been a Type 1 diabetic for 40 years. I would suggest that you wait to take your Lantus shot until you normally take it the next day. You may need to check your blood sugar a couple extra times and may need to increase your Novolog dosage at one or more meals. Just be careful and take less rather than more to be safe. Good luck.