Does Lynda.com list any specifications for the specific software(s) you want learn? I would assume they should have some details like the operating system the software(s) run on.
I am not familiar with GIS related software or the profession itself. I would guess that you generally need a laptop with an Intel CPU (preferably quad core if it is within your budget) and a workstation class graphics card like an ATI FirePro or nVidia Quadro because they have software drivers that are more stable and optimized to run professional software that are graphically intensive. Although I would say that a laptop with a gaming graphics card can work in a pinch. In other words, you are probably looking at a workstation laptop which can get pricey.
Assuming the course is lead by an instructor, it probably would be best for you to ask him / her for some suggestions. I suggest you look at the Lenovo ThinkPad W series laptops; assuming the software(s) you will be learning needs to run in a Windows operating system.
http
/shop.lenovo.com/us/en/laptops/thinkpad/w-series/