The community of Sonnenfeldt, the original name of what is now Beaubier, emerged in the early 20th century amid widespread homesteading in southern Saskatchewan. Homesteaders, lured by the Dominion Lands Act's offer of 160-acre quarter-sections for a nominal fee, settled the region's fertile prairie soils to pursue wheat farming and other agriculture. This influx was part of a broader wave of immigration to the Canadian prairies, where settlers cleared land, built basic dwellings, and established small farming operations despite challenging conditions like harsh winters and isolation. By 1918, Sonnenfeldt had developed sufficiently to support a local school, attracting educators to serve the growing population of families.

The construction of the Canadian Pacific Railway's Bromhead-Minton branch line in 1926 transformed Beaubier (formerly Sonnenfeldt) into a key siding, facilitating transportation of grain and supplies while accelerating settlement and economic activity. This railway extension connected remote farming areas to larger markets, drawing more homesteaders and enabling the rapid buildup of infrastructure. Soon after, essential services took shape, including a post office opened on August 1, 1927 to handle mail for scattered rural residents and the erection of the community's first grain elevator to store and ship wheat harvests. Small businesses, such as general stores and blacksmith shops, also appeared to cater to farmers' needs for tools, provisions, and repairs, laying the foundation for sustained agricultural development in the area.

The 1918 influenza pandemic, known as the Spanish flu, reached Saskatchewan in its devastating fall wave during September and October, rapidly spreading through rural communities via returning soldiers and rail lines. In rural areas like the district around Sonnenfeldt (now Beaubier), the outbreak led to widespread school closures as public health measures to curb transmission, leaving isolated homesteaders particularly vulnerable due to limited medical access and high population density in small settlements. Saskatchewan recorded approximately 5,000 off-reserve deaths from the flu between 1918 and 1919, with over 3,900 occurring in 1918 alone, disproportionately affecting young adults aged 20 to 40 who comprised the majority of victims owing to the virus's severe pneumonia complications.

Amid this crisis, Lucy Eleanor Beaubier emerged as a key figure in the Sonnenfeldt community's response. Born on 25 March 1894 in Brandon, Manitoba, to David Wilson Beaubier and Lucy Ellen Horner, she earned a Bachelor of Arts from Brandon College in 1917 and began teaching at the Lorraine School near Sonnenfeldt in the summer of 1918. As the flu struck in the fall of 1918, with schools shuttered, Beaubier volunteered as a nurse, organizing care for stricken residents by setting up sick rooms across the district and conducting house-to-house visits to check on the ill, even as she began showing symptoms herself. Her efforts exemplified the self-sacrifice common among young educators and volunteers in rural Saskatchewan during the pandemic.

Beaubier succumbed to the influenza on 5 November 1918 in Tribune, Saskatchewan, at the age of 24; her body was returned to Brandon for burial in the local cemetery. In recognition of her heroism, the village of Sonnenfeldt was renamed Beaubier in 1925, with the post office formally adopting the name in 1926, honoring her sacrifice amid the broader tragedy that reshaped rural life in the province.