In How to disable my netbook's touchpad when a usb mouse is connected I could not find an answer for my question.
Some laptops have drivers that automatically disable touchpad when external mouse is connected. My three-years-old toshiba's drivers does not have such option. Is there any software with such functionality? Answers to mentioned question say to use driver's option. I don't have that driver and thus don't have such option. What can I do?