Oh, sorry. I’m using Unicode runes; you should see them as long as you have an Unicode font covering that alphabet (some free fonts that do include and Code2000).
Thurisaz is the rune for the /θ/ sound, as in English “think”… or, well, “Thor” (it’s actually the source of the old English letter thorn, or þorn, before they changed it to “th”). Since toki pona doesn’t has a /θ/ sound, it doesn’t need it. The rune for a regular /t/ is ᛏ, Tīwaz.
AFAIK, for the ancients the rune names were just names, not mystical “meanings” as new-age dudes came to think. So I don’t think old Þórr will mind my not including the letter of his name. (It’s true that the people of old ascribed magical properties to runic inscriptions, but the magic was in the words, not in the alphabet. Inscriptions in the Latin alphabet were just as magical.)