When I try to put her leash on to go for a walk, she runs and hides, making it a game. I've tried luring with treats, but running and hiding seems to be more fun for her.
I would start having her drag around a light 4 foot leash while you're home, so that when it's time to go outside you can easily grab the leash and bring her out without giving her a chance to run. She needs to break the habit and learn that going outside with you is the best option and the most fun, always make it a positive experience with toys or treats and after a week or so of this she should be easier to leash up.
Do NOT leave the leash on while you are out of the house, this would be a safety hazard. When you come home I would casually call her into an enclosed area using treats (no leash in view) like a bathroom and then go grab the leash and attach it when she has no where to run and hide.
Definitely do not chase her! She will continue to think it is a game and it make it more difficult to break her of this. When you have some time, I would recommend sitting on the couch or a chair with the leash next to you or in your lap. Let her approach you and sniff the leash. Praise her for coming to you! Attach the leash and allow her to be with you with the leash on for a little while and take it off. Eventually, you can progress to leading her around the room with the leash on before taking it off again, then on to take her out for a short walk and coming back in to take the leash off again. Always remember to give praise and treats for everything she does right! Do not scold her for any wrongdoing, and instead try ignoring her until she complies. I'd like to mention, this last bit can sometimes be the most frustrating for the owner because you hope to see immediate results and it can be hard to withhold showing frustration to your dog and scolding her, but patience can really prove worth it if you stick with it!