Dog urinating indoors

[avz10]

We have a six year old miniature dachshund. She was basically fully house trained, until our Scotty died in December. She used to follow her when going outside.
After the initial grievance, we are stuck with this problem. She does it behind our back, so we never see her.
Most of our floors are tiled, so she urinates in our bedroom on the carpet and on any item made from material lying on the floor.
I have sprayed our carpet on different occasions with recipies read on the internet- vinegar, cayenne pepper, lemon juice. Someone advised me to use citronella oil, but have not used it
Any advice please