Hornet trouble

I have a problem. A fairly big problem. Here's a picture. It is a European Hornet. They are getting into my house in multiples. One or two nearly every night. We figure they are coming in with the cats or when we open the door to put out the torches or check the coals or whatever, though we never actually see them come into the house. I hope that is what is happening. I hope they don't have another way in that is just an open door for them. Their own personal entry into our abode. Now, you entymologists out there can tell me how gentle these guys are, how unaggressive unless threatened (what threatens them?) and how unlikely they are to sting unless provoked, but you see, I am allergic. Very allergic. I get stung, I die. That kind of allergic. So, just pretending they aren't there is not really an option for me. Last night one came in and then between my calling for my dh and his arriving, it disappeared.... and he couldn't find it. He waited up until almost 0100, but no sign. Now, I know it was there, it was a good big one, hovering by the door about knee high. Looking menacing. I didn't sleep so well, I can tell you. This is really not very good. Did you know the European Hornet hunts at night? I didn't know any stinging waspy type critter did. In fact, I thought that was a safe time for most bees and wasps. Ha! Silly me. Turns out these guys actually fling themselves against windows trying to get to lights, hurl themselves into glass. Now, if they like light, for heaven's sake, why don't they hunt diurnally and sleep at night like a normal bee! I am not a happy person right now.