Canadian passport holder - apply for a Chinese tourist L type

Hi,
I hold a canadian passport and I am working under TN visa in Houston.
For next year (April 2016), I booked a trip to Thailand with a stop over in China (10 hrs in Beijing). To my understanding, I need a chinese tourist L type, and the tourism agency through which I booked this trip (Affordable Asia) does not provide this service. Could I apply for this L type, here in Houston, or should I apply in Toronto?
Thank you,
Cristina Cozma