“Torchlight” is a less-common than 10,000 word – and “torch-light” is less common than the first 100,000.  I am fascinated that both appear side by side in Chapter 9.

• 09.003 well behind their torch-light
• 09.005 with red torch-light,
• 09.011 in torchlight)
• 09.022 taking the torchlight with them
• 13.044 and far beyond the reach of their torch-light.

Two-word word, one word, or hyphenated are all acceptable in OED.

“ˈtorch-ˌlight, n.” OED Online, Oxford University Press, June 2017, http://www.oed.com/view/Entry/203510. Accessed 21 September 2017.