Ronaldo had not found the net for the league leaders in a month due to suspension and a rare blip in form.
But he returned to the scoresheet in his side's 2-0 Champions League win at Schalke on Wednesday, a result that gives the holders an excellent chance of reaching the quarter-finals, with the second leg of the last-16 tie penned in for March 10.
Ronaldo's goal - his 37th in all competitions - is sure to lift his confidence against an Elche side he has tormented in the past.
The 2014 Fifa Ballon d'Or winner has made just two appearances against Elche, but has bagged six goals in the process.
First came a double in a thrilling 2-1 win at Elche in September 2013.
Elche thought they had secured a famous draw when Richmond Boakye equalised in the 90th minute, but Ronaldo - who had netted earlier - stepped up to convert a controversial stoppage-time penalty.
And while he missed Real's 3-0 home win in the reverse fixture last term, he made up for it with a four-goal haul as Carlo Ancelotti's men romped to a 5-1 success in September.
Real Madrid goalkeeper Iker Casillas feels Ronaldo's header in the Schalke win is crucial for his confidence.
"When Cristiano goes one, two or three games without scoring, even though he continues to provide assists, it's treated as big news," he told the club's official website.
"We were calm about it all because we knew he would score. It was important that he did because it gives him, as well as the rest of us, confidence."
Defender Raphael Varane echoed the thoughts of Casillas in an ominous sign for Elche.
"It's always good when Cristiano Ronaldo scores, because it helps a lot," he said.
"When he's in form, he can change a lot of games. It's good for him and for the team. When he scores, he always has more confidence."
With an incredible 72 goals in 23 Liga matches, Real, who are still yet to draw a league game this season, will be licking their lips against the second-worst defence in the competition.
Elche were thrashed 6-0 by Barcelona last month, but come into the Real clash on the back of successive victories. They kept a clean sheet in both, too, as triumphs over Rayo Vallecano and Eibar moved them further away from the relegation zone.
Four wins in their seven Liga matches in 2015 represents a significant turnaround, but adding to that tally this weekend would be a major shock.
James Rodriguez (toe) and Luka Modric (thigh) will be absent for Real, but any chance of an upset seems unlikely - particularly given Ronaldo's return to form.
