My Live Mail Calendar has suddenly disappeared

For some time I've had a LiveMail (under Vista) with an addressbook and Hotmail calendar.  Because the institution I used to belong to was about to close down my e-mail address, I've been running for a while with two e-mail addresses, the old institutional one, and a hotmail address.  The two addresses appeared as two accounts in the left hand margin of LiveMail.

When my old e-mail was closed down by my ex-institution, I deleted the LiveMail account that related to it in the left hand column, and began running with the new one.  For a day or two all was well, and I had my old addressbook and calendar as usual.  Then suddenly today it began asking me to sign in to Live Mail (which I hadn't previously had to do).  Since my Live Mail sign-in id had been the old institutional e-mail address, I changed over to my new hotmail address, with the same password.

I then tried to do some e-mailing and realised that it couldn't retreive any entries from my address book, and the calendar display on the right of Live Mail no longer displayed any of my appointments.

I've managed to reconnect to my address book (thank you, MS Community!), but can't see any way to reconnect to my calendar. 

Any suggestions?