At a session at its Ignite 2017 conference called 'Surface product engineering behind the scenes, and deep dive on the new Surface Pro', Microsoft confirmed that the LTE-enabled Surface Pro will be made available on December 1. According to the spokesperson, you can already find these devices on the company's product page, but it still doesn't seem to be listed.
The Surface Pro was originally announced at an event in Shanghai back in May, and a cellular variant was promised, but there hasn't been much talk of it since then. It's been speculated that they will be announced at the Future Decoded event in London next month, where Surface chief Panos Panay will hold a keynote.
Unfortunately, the cellular variants will only be made available in the Core i5 flavors of the device, which come with either 4GB RAM and 128GB of storage or 8GB RAM and 256GB of storage, along with Intel HD Graphics 620. These configurations mirror the pre-order information that a UK site listed last week.
Of course, it's possible that Core i7 models may come later, similar to how the different colored Surface Laptops were only available with a Core i5 at launch.