I have a similar looking lily. Mine stays open till the sun is directly on it and it closes and then reopens the next night. You can try to snap a picture early morning. That's when I get my pictures.
My lily grows like mad over the summer. Takes up almost my whole pond. I started with one and I have so many now. I keep dividing them up and putting them in pots. I guess I live in the ideal climate for this plant.
Because I have so many I often run out of space and stick them in my indoor tanks (my smallest lily). Some survive, some do not, they need good light, my tank lights are not great (cheapest I could find), but if you find a good light you should be fine. I have one in my tank that's been for months now.
If you have some sort of container/stock tank you could put the big plant in there with a minnow or two to keep it fertilized and and rig some light over it.
Good luck! I find they are dormant in 'winter' here (dormant as in just a few leaves and not many flowers), which isn't really winter, but I guess they just take a rest. I thought mine had died, but as soon as it got HOT again, it went crazy.