How to select rules whose first element in the lhs is a particular element

Question

I mined rules using the apriori algorithm in R.

library(arules)
data("Adult")
rules <- apriori(Adult, parameter = list(supp = 0.05, conf = 0.5, minlen = 2, maxlen=5),
                 appearance= list(rhs=c("native-country=United-States"),default="lhs"))

From the rules generated, I extracted rules with two elements in the lhs making sure that these rules had the variable of interest ("race=White") in the lhs.

rules.sub2 <- subset(rules, size(lhs)==2)
item <- "race=White"
rules.sub <- subset(rules.sub2, lhs %in% item & size(lhs)==2)
#inspect(rules.sub)
inspect(sort(rules.sub, by = "lift")[1:10])

The results looks like this

     lhs                                         rhs                            support    confidence coverage   lift    
[1]  {education=Some-college, race=White}     => {native-country=United-States} 0.18041849 0.9486489  0.19018468 1.057080
[2]  {marital-status=Divorced, race=White}    => {native-country=United-States} 0.11031489 0.9479240  0.11637525 1.056272
[3]  {occupation=Sales, race=White}           => {native-country=United-States} 0.09524589 0.9474542  0.10052823 1.055748
[4]  {occupation=Exec-managerial, race=White} => {native-country=United-States} 0.10595389 0.9453782  0.11207567 1.053435
[5]  {relationship=Own-child, race=White}     => {native-country=United-States} 0.12327505 0.9453603  0.13040007 1.053415
[6]  {race=White, income=large}               => {native-country=United-States} 0.13725892 0.9419699  0.14571475 1.049637
[7]  {education=HS-grad, race=White}          => {native-country=United-States} 0.25783137 0.9406887  0.27408788 1.048210
[8]  {occupation=Adm-clerical, race=White}    => {native-country=United-States} 0.08803898 0.9392748  0.09373081 1.046634
[9]  {race=White, hours-per-week=Over-time}   => {native-country=United-States} 0.22290242 0.9389392  0.23739814 1.046260
[10] {education=Bachelors, race=White}        => {native-country=United-States} 0.13484296 0.9363094  0.14401540 1.043330
     count
[1]   8812
[2]   5388
[3]   4652
[4]   5175
[5]   6021
[6]   6704
[7]  12593
[8]   4300
[9]  10887
[10]  6586

From these rules, I want to extract rules whose first element in the lhs begins with "race=White". I tried the code below, but that won't work. I am not sure how to do this. Any help would be much appreciated.

# Extract the first elements of lhs in the rules
first_elements_lhs <- sapply(slot(rules.sub2, "lhs"), function(x) {
+   elements <- slot(x, "items")
+   if (length(elements) > 0) elements[[1]] else NA
+ })