With 5,000 parishioners and no money for a new church, he had a huge plastic tent erected in the parking lot.
Unfortunately, it acted like a big greenhouse. People began dropping in the 120-degree heat. A handful of swamp coolers made little difference. And the distribution of fans made from Popsicle sticks taped to paper plates was even less effective.
"Almost every weekend we called the paramedics because people were fainting inside," Lucas said. "We had 40 volunteers do CPR classes in case something terrible happened."
Winter was no better. People shivered as cold winds battered the tent and sandstorms blew dust through the flaps. There were no bathrooms; portable toilets lined the parking lot. The church was a study in hardship and discomfort.
But now the tent is empty. Across the parking lot stands a gleaming new sanctuary outfitted with actual pews, a granite altar, chandeliers, bathrooms, air conditioning and heating.
"I am very proud of this community. Even though they are poor, you have no idea how generous they really are," Lucas said, surveying a church that seemed impossibly luxurious compared with the tent. "In these hard economic times, when people think there isn't anything to be thankful for, we now have this."
Our Lady of Guadalupe is the poorest Catholic congregation in Riverside and San Bernardino counties, and one of the poorest in the state, church officials said. It is made up largely of Latino farmworkers often living in ramshackle trailer parks dotting the eastern Coachella Valley. There is also a large contingent of Purepechas, indigenous people from the Mexican state of Michoacan, who attend.
Despite the poverty, Lucas launched an ambitious fundraising effort two years ago for a new church.
But in a place where annual incomes often fall under $10,000, where unemployment is rife and where Lucas says the average parishioner drops about $3 a week into the collection plate, the odds were against him.
Then the money began trickling in. It arrived in crumpled envelopes: a dollar here, two dollars there, a fistful of change. In one case a woman brought in a bag of dates.
"She said, 'Father Lucas, I have no money. Sell these dates and use the money to build the church,' " Lucas said. "If she came with a bag of dates, then I will use the dates to build a church."
That spirit soon infected others.
"Even though they say we are the poorest of the poor, we had the discipline to keep it up," said Gilbert Medrano, 40, as he helped hand out boxes of food to a steady stream of members coming through the door.
"I am an unemployed carpenter but I have given what I could, and some weeks that wasn't very much."
In the notorious Duroville trailer park, which the U.S. government is trying to close because of health and safety concerns, Aron Felipe's family regularly contributed.
"We would give $5 or $10, but we gave every week even if it was very little," said Felipe, 18, who had just finished working in the fields.
A few blocks away, Patricia Huente said the church dominated life in the park.
"I was surprised we could raise so much," she said. "It's a high poverty area, but little by little it became enough. If you give away more, you receive more back."