Yes this, or the other possibility is that the lady is having plenty of care visits and while theoretically able to cope, if she has dementia or maybe even just severe anxiety, she may be forgetting and getting herself wound up in between times - we had a very sweet elderly neighbour who was similar, her family weren't local but she honestly had so much input, carers 4 times a day, meals on wheels, district nurse daily, GP weekly, local befriender charity took her out 3 times a week, people from the local church visisted near enough daily plus lots of neighbours popping in for tea and chats as well. No matter how many visits she'd already had that day it took her approximately 30 mins being on her own to get lonely and upset and within the hour she'd be ringing round anyone who's number she had sobbing and distressed, sometimes with imaginary problems with getting food or prescriptions or hospital visits (if you went over there to help out she'd have plenty of food in, or the prescription would be being delivered that day), sometimes she was just feeling sad or afraid of something. She would say things like 'no-one's been near me for days' when I knew that simply wasn't true (I'd have seen all her visitors coming and going all morning!). If you went over and sat with her for a bit and had a cup of tea and a chat she'd be delighted and apparently soothed and calm, yet 30 mins later she'd be back on the phone to me or anyone else who'd pick up saying she was horribly lonely again. Several times we found her wandering the streets in her nighty at odd times of day crying and approaching strangers saying she just needed a bit of help when there was no more help she could possibly have
.
She ultimately just wanted to be a bit more looked after bless her, in the olden days she'd have lived with family (and probably driven them a bit mad!), these days she probably would have been better off in a care home but any time the capacity assessment social workers came around she would suddenly be bright as a button, coping fine on her own, definitely didn't need/want to leave her own home etc - I think all that was driven by fear of care homes/institutions which is fair enough given what they must have been like in her youth, a lot of elderly are exactly the same.
Anyway as to what to do, if you are worried the right people to speak to are adult social services - they can do an assessment and perhaps put in place some carers - or maybe try Age Concern, they may be able to suggest things like local befriending services, they can't help with care but can help with the loneliness thing?