To get sheltered accommodation locally you will need to be registered with b-with-us
PennineLancashire - Who Can Use the Service
The vacancies are advertised there. Park view, Kirk house, Merlin court are just a few that I know of, who advertise their vacancies there.
When you apply, you get a home interview to assess your need and allocate priority for rehousing.
The 'die off rate' is more than other types of housing (I know that sounds insensitive but how can I put it otherwise), so vacancies crop up often.