Is there any way to reduce the length of the philtrum without resorting to a lip lift?

Short answer: No
The ideal candidate for the Elelyft, or upper lip lift, is someone with a philtral length of 14mm or longer, no upper dental show, and/or a thin upper lip. The nasal base to mouth width ratio needs to be taken into consideration to avoid leaving the lip corners down. 
A lip reduction can be performed with a lip lift if you are concerned about making the upper red lip too big. 
Gary Linkov, MD

19 mm indicates a long upper lip. The ideal length of the upper lip for a female is 11-13 mm. A LeFort I surgery will correct the condition known as "long face syndrome" but it will not shorten the upper lip. An upper lip lift performed as a single procedure will not thicken the upper lip. The upper lip surgery is performed in the office with IV sedation or local anesthesia. There is significant lip swelling for 3-4 days but most patients look good at 1 week when the sutures are removed. This is a very commonly performed procedure. Good luck

In order to reduce your long philtrum, a lip lift will need to be performed. This will pull your lip vermillion (the red part) higher and may make your upper lip look more thick. You may need to combine this with a lip vermilion reduction as well to compensate for the gain in thickness. Hope this helps!Johnson C. Lee, MD 
Board-Certified Plastic Surgeon

It would help if you attached photos of your face. 
Generally speaking, as a rule lip lift does two things: reduces philtrum length & makes upper lip fuller by pulling it up. If we shorten the philtrum, we automatically make lips fuller. This is a key characteristic of a lip lift. 
best regards, 
Piotr Osuch, plastic surgeon, MD, PhD