My own two cents as having just been through this...lenders in Ontario don't 'foreclose', they employ 'Power of Sale' provisions which form part of the mortgage contract you would have signed and means that they will ultimately take ownership and sell the house. The term 'default' is the key in all of this.
Is your mortgage CMHC insured? - If so, there is a protocol the lenders must follow to ensure they get their $$ from the insurance fund. If it is not at the lawyers yet, consider it nothing more than an insidious threat from their collections group.
My experience as a CMHC insured mtge is that after two missed payments (variable depending on the lender, as I had hit three - but also two at a later date), you will receive a letter from lender's solicitors indicating that they are acting on behalf of the lender and are activating the POS clause. There is lots of mumbo jumbo that makes it look like you have to pay the full mortgage amount plus late fees plus lawyers fees etc. etc., but unless your mortgage is at the renewal stage (in ON), then you just have to make up late payments plus other ancillary fees.
Depending on the type of POS clause in your contract, the letter from the solicitors will indicate that everything has to be paid by such date (usually 38 or 45 days after what they have determined as date of default).
Having worked in finance many moons ago, concur that each payment made should be applied against the earliest missed payment. 180 days late sounds suspicious to me as the lender would want to / have to reduce their risk much before that time.
My (non legal, non binding) opinion is that as long as you keep paying regularly and make some effort to make up the lost payment - things should be good. It is only when the lawyers get involved and you receive the dreaded registered letters (which absolutely must be registered or hand delivered advising about the POS), that you know things have gotten to the more serious stage. The rest is hot air, at least as far as my own situation had unfolded.
Good non soliciting website for some legal type info on Power of Sale is seems to be: http://genesismortgages.com/genesis-associates-mortgage-brokers-on-mortgage-legal_menu.html or you could read the mortgage act for Ontario (although the former is a lot less dry).
Good luck going forward - and again, above was my experience flirting with POS. I have never made it past this stage, so can't opine in any great detail what the next steps are.
Cheers.