How to protect outside cable wire from myself?
If this is a cable TV wire, your best solution is to get it re-run properly by the cable TV company. Unfortunately, that sometimes can only be arranged by figuring out when it would be least inconvenient to you to have the cable out for a while and then running over it with the mower, etc - at least in my experience they are good at coming to fix stuff, bad at fixing it when it ain't broke. Your Mileage May Vary.

Now, if you'd like it run in conduit this time, they are not going to go there, but they generally won't mind if you do, so you might run the conduit (presumably in the "not all the way around the house direction" unless there's some good reason for that) before you mow the lawn and hit the improperly installed cable. If you can avoid most of the around the house run by having an inside the basement run, go ahead and run that cable (they won't do inside cable work, for the most part) and have it handy for connecting to their new cable.

I had a ridiculous replacement cable run when our old one filled up with ice at a bad connector, and for obvious and understandable reasons the installer did not want to run a new one where the old one was going along the icy roof, so he tossed one over the edge and down the outside of the building to the ground. That installer suggested calling back when things were warmer to have a better one placed, or getting an inside cable run and calling back to avoid the roof entirely. I had the inside cable run, called back, and they would not come switch it over; so it sat for several years until I next had a problem with the cable service they would come fix, at which point the installer was happy to switch to the inside cable. I did not actually attack the dubious cable, but I considered it...