The two notable writings using the Tengwar letters that I can recall are the inscription on the Ring (in Black Speech) and "Namarie" which Tolkien (I believe) penned for his commentaries upon the text in the Donald Swann "The Road Goes Ever On" cycle (in Sindarin, I also believe). Both show distinct gaps between words. The Swann book is literally buried in my office at the moment, so I can't go look it up, but if I'm remembering right, a version of it Tolkien penned did not use the tehtar (vowel marks), but instead used other actual letters for the vowels. Either way, there are definitely spaces between the words. I'm pretty sure. Well...
