Ask Mr. Smarty Plants

Yucca elephantipes is native to southeast Mexico and Guatemala. As such, it is not in our Native Plant Database. The Lady Bird Johnson Wildflower Center is committed to the growth, propagation and protection of plants native not only to North America but to the areas in which they naturally grow. The yuccas that grow natively to Arkansas are Yucca arkansana (Arkansas yucca), Yucca filamentosa (Adam's needle), Yucca glauca (Soapweed yucca), and Yucca glauca var. glauca (Narrow-leaf yucca).

From the  University of Oklahoma Department of Botany and Microbiology we found this article on  Yucca elephantipes, which says theirs has never bloomed.

University of Florida Extension Spineless Yucca has these notes under "Use and Management:"

"The two to three-foot-tall bloom is produced on top of the stalks once the plant is 8 to 10 feet tall. Spineless Yucca grows easily in full sun or partial shade on any well-drained soil. Do not plant Yucca unless drainage is superior. Yucca grows well as a houseplant in a well lighted area."

Yuccas require a specific moth for pollination, and if the right moth isn't around, you won't see fruit develop even though the plant produces flowers. Since your plant is not native to your area, the yucca moths that pollinate it will not be present, either, but that still doesn't explain why your plant doesn't bloom. One more thought: this plant is cold tolerant in Zones 9b through 11; Boone County, in northwestern Arkansas, is in USDA Hardiness Zone 6a, which means the plant shouldn't be able to survive outside, much less bloom. Some of the information we saw referred to it as a house plant, but with a projected height of 30', we don't see how that would work. You already said it was in the sun, so we are assuming it is outside. The only other possibility is that you are feeding it with too much nitrogen-high fertilizer, which will frequently retard blooming.