Hi ceebee,
When you go "low", what is your reading? (Sometimes when the body is used to higher than normal levels it can seem like a low just to be in range). I would not suspect the Lantus as causing your evening lows. Lantus is a long-acting insulin that takes a few hours to even ramp up so, unless you are maybe injecting into muscle, a half hour after taking it should not see you crashing. I might look to your 2nd daily dose of metformin along with the timing of your dinner meal and what you normally eat at it, as the possible area of improvement.
The rule of thumb for a "low" is to eat/drink 15-20 grams of fast-acting carbs (juice, Glucose tabs, candy, etc. NOT ANYTHING WITH FAT & PROTEIN), then test again in 15-20 minutes. If not in range - eat 15-20 grams more sugar. Test again. Repeat until you are in acceptable range. THEN... if you are not expecting to have a meal within 90 minutes - eat a snack with fat & protein to carry you over till your next meal. It's important that you bring up a low quickly with simple carbs (think: straight sugar), as protein & fat (think: chocolate) take too long to bring you up quickly. The fat & protein snack or meal you have next will keep you from going low again; it sustains you till your next food intake.
If you are actually going low in the evening... bring it up with the OJ if you like but you should eat a snack before bed to keep you going till breakfast. Test around 3:00am to see what your sugars are like (and to make sure you aren't going low throughout the night). If you are and if you continue to regularly go low in the evening, then call your doc and get those meds adjusted. You shouldn't have to "feed the medications" to maintain control. Doing that is usually an indication that the meds are too high or timed improperly. Maybe taking your Lantus in the morning might work better? At least the routine of your lows might be adjusted to daylight hours as opposed to evenings & bedtimes. Again, something to discuss with your doc.
And of course, log everything