@Alex Being the world’s leading expert on lightning strikes, I would think you would be ok with an outdoor antenna as long as you keep it reasonably low down. It shouldn’t be even close to being the highest point on the outside of the house. You should think about routes whereby electric current can somehow be drawn up/down from/to the earth (or the opposite direction) into/away from the antenna as the electric field underneath a thundercloud either attracts electrons up into high points or repels them away from such points down into ground. The high point then becomes charged and has a very strong electric field around it, the field strength depending critically on how sharp any point may be (‘point effect’). If high enough, this field can cause air to break down and start a streamer that can build into a lightning strike. If there are other rather higher points on the building then they will be the unlucky candidates for the greatest point effect and your antenna will not be the site of such buildup. Also consider insulation and the resistance of paths from ground to your antenna, especially when everything is wet.
Indeed, as long as the antenna has line of sight or something like it, it can presumably be as low as you like as long as stray cows/tourists/relatives don’t walk right in front of it. Being low down means that the likelihood of high wind damage is reduced, especially if you can arrange for the house itself to give protection from the prevailing winds, although I appreciate that this is not always possible, if the line to the basestation is simply on the wrong side of the house.
I did think about getting hold of two fibre media converters and inserting them with a short length of fibre inline to make a break in my copper ethernet cable, so as to completely break the electrical circuit, hence no route to/from ground for charge buildup in the antenna or a current surge from a lightning strike that destroys all your kit as has happened to me with modems.