With awareness that this question is many years old, it bears mentioning that the other answers all essentially assume that the loans are equivalent on all terms aside from the down payment (and impact to monthly payments as a result of a different down payment). It's important to note that this may not be the case. It would be somewhat rare for a 10% difference in down payment to have zero affect on loan terms for most typical mortgages.
Lenders consider many factors when writing a mortgage, and they have many variables to adjust for different scenarios. The size of your down payment can have a significant impact on the terms of the loan. Lenders generally like to see larger down payments from a risk perspective (a larger down payment means a safer loan to value ratio). As such, it's often the case that the mortgage products with the best terms have higher down payment requirements - for instance, the lender's best rates may only be available if you put 20% or more down up front. So, putting more money down may in fact mean that your loan is written at a better interest rate.
Additionally, many lenders will have personal mortgage insurance requirements (known as CMHC in Canada or PMI in the US) based strictly on down payment size. In Canada, if your down payment is less than 20%, the lender is required to book CMHC on the loan - so even though the finances of the loan itself won't be different in terms of principal and interest payments, if that 10% extra cash would have brought you above the 20% threshold, you would see significantly different monthly payments (because you wouldn't be carrying the insurance).
All that said - if your loan would be 100% the same regardless of you putting that extra 10% down up front vs adding it to your first payment, then the other answers are relevant. However, it's important to understand the big picture in terms of all terms of the loan, before making this sort of decision. If you're already working with a bank or a mortgage agent, they can likely explain the difference for you and show you the actual numbers, which should make the decision easy.