Pin one is in the one you indicated. Lower left in your picture.
That is how I would read the indications given on page 8 of the datasheet.
Additionaly, pin 1 is usually the lower left pin when the chip is positioned to read the markings. This isn't always true, but it is generally how it is done. In this case, it also agrees with the datasheet and dot for the index mark.
In response to comment from Michael Karas:
Yes, I would be careful with the "lower left corner is pin 1." It is very much just a starting point or a sanity check - or when you've got nothing left to go by.
Always check the datasheet and go by what it says.